The assumption that gains of OAM beams are the same in different propagation directions is widely adopted in current OAM-based radio communications. But this assumption conflicts with the spatial distribution characteristic of OAM beams where the energy of OAM beam is focused on a circle surrounding the beam axis [1]}, [2]}. Considering the spatial distribution characteristic of OAM beams, in this paper a new OAM spatial modulation (OAM-SM) scheme is proposed for multi-antenna millimeter wave communication systems. Main contributions of this paper are list as follows:
